More than likely the Forward band broke and the trans will need rebuilt. This problem seems pretty frequent. The band will crack right where the apply piston engages it. You should be able to verify this by removing the lower pan and taking the filter off and looking up near where the tube goes up into the trans on the passanger side. There is a cover on the back side of the trans with 3 bolts holding it on and this is the forward apply servo. Directly in front of this towards the inside of the case is the apply pin from the servo piston and you can look where it is making contact with the band, or the broken piece may be laying in the pan.
